The present invention relates to a method and/or architecture for implementing Universal Serial Bus (USB) peripheral devices generally and, more particularly, to a method and/or architecture for improving electromagnetic compliance (EMC) performance in a USB peripheral device.
Universal Serial Bus (USB) devices normally need to be certified by standard regulatory bodies (FCC, CE, etc.) for electrical compliance before they can be sold in a particular market. In order for a USB device to pass the appropriate electromagnetic compliance (EMC) test, the device is subject to a few thousand volts of electromagnetic fast transient burst (EFTB) or electrostatic discharge (ESD) signals.
Conventional USB microcontrollers have internal analog circuits that resist a high degree of electrical disturbance. Additionally, board layout and external component selection of conventional USB microcontrollers influences overall EMC performance. However, if a vendor desires to certify a USB device at a tolerance that is well above the specification of the part, some type of technique must be incorporated into the device to accommodate such extreme conditions.
Conventional approaches for implementing EMC compliance include implementing external EMC suppressers. The external EMC suppressers are placed on data and supply lines of the USB microcontroller. Such suppressers provide a reliable way of handling unexpected electrical disturbances. However, such an approach increases the overall cost of the device since it requires additional parts external to the device.
It would be desirable to implement EMC compliance in a device without adding to the overall complexity and/or total cost of the device.
The present invention concerns an apparatus configured to communicate through a differential bus to a device. The apparatus may be configured to disconnect and reconnect the device in response to an abnormal reset event to provide enhanced electromagnetic compliance (EMC).
The objects, features and advantages of the present invention include providing a method and/or architecture for implementing electromagnetic compliance (EMC) in a device, such as a USB peripheral device, that may (i) allow a device vendor to improve the performance capabilities for ESD and/or EFTB events at no additional hardware cost; (ii) allow an end user to enjoy the benefits of a device that is less likely to fail when subjected to extreme electrical disturbances; (iii) provide improved EMC performance at no additional material cost; and/or (iv) allow vendors of USD devices to be able to produce more reliable devices without additional unnecessary costs.